Data from: Predictable males and unpredictable females: repeatability of sociability in eastern water dragons

There is growing evidence for consistent among-individual variation in individual sociability (e.g., tendency to be sociable) in a number of species. However, sexes often differ in their social behaviors, as well as the selection pressures which they experience. This may translate into differences in repeatability of sociability, although this has not yet been tested. Here, we investigated whether eastern water dragons (Intellegama leseurii) exhibited evidence of consistent among-individual variation (i.e., repeatability) in 4 different measurements of sociability. Specifically, we measured sociability in 4 ways (degree, centrality, proportion of time spent being social, and number of preferences), and tested whether there was evidence for sex differences in the repeatability of these sociability measurements, or whether observed levels of repeatability could be explained by a stable social environment. Our findings provide new evidence for sex differences in social personality: we found that males were significantly repeatable in 3 of 4 sociability measurements (degree, centrality, and proportion of time spent being social), whereas females were not. Further, we found that these differences were not a result of differences in the dynamics of the social environment. We discuss our findings in the context of sexual selection, as well as sex differences in the evolutionary drivers of social behavior.

越来越多的研究证据表明，诸多物种的个体社交性（sociability，即个体的社交倾向）存在稳定的个体间差异。然而，两性的社交行为以及其所经历的选择压力往往存在差异。这或可导致社交性的可重复性（repeatability）出现分化，但该假说尚未得到实证检验。
本研究以东部水龙（Intellegama leseurii）为研究对象，针对4项不同的社交性测量指标，探究其是否存在稳定的个体间差异（即可重复性）。具体而言，我们通过4种维度量化社交性：社交程度、中心性、社交时长占比以及偏好数量，并检验两类问题：一是这些社交性指标的可重复性是否存在性别差异，二是观测到的可重复性水平是否可由稳定的社交环境所解释。
本研究结果为社交人格的性别差异提供了新的实证依据：我们发现雄性在4项社交性指标中的3项（社交程度、中心性及社交时长占比）表现出显著的可重复性，而雌性则未呈现该特征。进一步分析显示，此类性别差异并非由社交环境的动态差异所导致。最后，我们结合性选择（sexual selection）理论以及社交行为进化驱动因素中的性别差异，对本研究的发现展开了讨论。